Effect of adding probiotics to an antibiotic intervention on the human gut microbial diversity and composition: a systematic review

Introduction. Millions of antibiotic prescriptions are written annually in the USA. Gap Statement. Probiotics reduce antibiotic-induced gastrointestinal side effects; however, the effect of probiotics on preserving gut microbial composition in response to antibiotics is not well understood. Aim. To evaluate whether the addition of probiotics is capable of reverting the changes in alpha diversity and gut microbial composition commonly observed in adult participants receiving antibiotics. Methodology. A search was conducted by two researchers following the PRISMA guidelines using PubMed, Science Direct, Cochrane and Embase from January to December 2021 with the following inclusion criteria: (i) randomized clinical trials assessing the effect of antibiotics, probiotics or antibiotics+probiotics; (ii) 16S rRNA; (iii) adult participants; and (iv) in English. Once data was extracted in tables, a third researcher compared, evaluated and merged the collected data. The National Institutes of Health (NIH) rating system was utilized to analyse risk of bias. Results. A total of 29 articles (n=11 antibiotics, n=11 probiotics and n=7 antibiotics+probiotics) met the inclusion criteria. The lack of standardization of protocols to analyse the gut microbial composition and the wide range of selected antibiotics/probiotics complicated data interpretation; however, despite these discrepancies, probiotic co-administration with antibiotics seemed to prevent some, but not all, of the gut microbial diversity and composition changes induced by antibiotics, including restoration of health-related bacteria such as Faecalibacterium prausnitzii. Conclusion. Addition of probiotics to antibiotic interventions seems to preserve alpha diversity and ameliorate the changes to gut microbial composition caused by antibiotic interventions.